Right from the outset of a virtual server deployment, the intimidation factor can loom large. Identifying which servers and which applications to virtualize can paralyze even savvy IT managers.
How do you know which servers and applications to virtualize? How many virtual servers should you place on each physical server? And how can you ensure that virtualization helps your business to become more efficient and reduce costs? The key to getting all this right is performing a proper IT environment assessment before you begin the virtualization deployment process.
Assessing the existing IT environment
To ensure that a virtual server deployment will enable your company to become more efficient and reduce costs, you first need to build the business case for virtualization and map the business objectives of the company with the goals of your virtualization project. This requires identifying the kinds of applications you run, their function and centrality to company mission, and other factors.
If you don't have a grasp on your IT environment's physical resources, you cannot successfully virtualize those assets. So the first step is to analyze the current state of your servers and applications.
If you have worked in this IT environment for some time, you may assume that you know everything about the current infrastructure and may prematurely begin virtualizing. Blanket assumptions that aren't supported by an IT environment assessment are often incorrect. Why? Over time and as data proliferates, your infrastructure changes: Applications have been upgraded, administrators have made changes, and your past knowledge quickly becomes outdated. Take the time to identify which physical servers are installed, their resource utilization, and which applications and data reside on each server.
IT environment assessment checklist
List your current inventory of physical servers as well as their CPU, RAM, and disk configuration and which applications run on each of these servers. This list can take the form of a simple five-column spreadsheet.
Certainly, taking an inventory of servers and applications is important, But equally important, you need to understand the function and nature of these applications. How important are these applications to the company's business functions? What is the impact of having these applications suddenly become unavailable? Are these applications CPU-, RAM-, disk- or network-intensive? Does a given application depend on others to run? What is the required availability of this application?
By answering questions like these, you can determine which servers and applications to virtualize, which to leave alone, and the priority and sequence in which to virtualization servers.
At this point, you are likely wondering what your server consolidation ratio will be. If you can place 20 physical servers on a single virtual host server when virtualized, for example, your server consolidation ratio is 20:1. You can imagine how important this consolidation ratio is. The higher the ratio, the fewer host servers you need, the less space and infrastructure is required to support servers in your data center, and the greater the return on investment you can achieve for the virtualization project as a whole. The greater the consolidation ratio, the greater the management benefits you can derive from having fewer servers to manage.
So how do you determine this consolidation ratio? By understanding your applications, you can get a good idea. But unfortunately, you can be certain of your server consolidation ratio only after you virtualize your servers.
Goals for virtualizing your IT environment
Now you need to identify goals for the virtual server deployment project itself. Perhaps phase one of your project, for example, is to virtualize all noncritical servers so you can determine server consolidation ratios -- that is, the number of physical servers that you can virtualize and place on a single physical server -- and provide a proof of concept. On the other hand, you could have goals such as the following:
- virtualize all critical servers and place them in a high-availability and load-balanced resource pool;
- virtualize all end-user desktop systems; and
- virtualize all physical servers that have CPU utilization of less than 50%.
Your goal should also identify whether your project is a success. Goals should be tied not only to the resources that have been virtualized but also to the performance of these resources prior to and following virtualization. From the end-user perspective, these applications' performance should be no worse than when these applications ran on a physical server.
Most important is that you take the time to understand your servers and applications, set goals for your virtualization deployment, and demonstrate that you have met your goals without undermining end users' experience.
Automated IT environment assessment tools
At this point, you might wonder, "Why can't an automated tool evaluate my IT environment for me?" The answer is that some tools can indeed assess your resources for you. These tools take an inventory of physical servers, identify applications, measure physical server utilization over time and then recommend the host servers on which to put virtual machines (VMs).
Two tools that can automate IT environment assessment are the following:
- VMware Guided Consolidation. VMware Inc.'s vCenter Server -- the virtualization software's management suite -- includes Guided Consolidation, which is installed separately but from the same DVD used to install vCenter. Guided Consolidation can identify physical servers in your domain and their hardware configurations (e.g., CPU, RAM, disk) and gather performance data from these resources over time. Combined with the data on your virtualization environment that Guided Consolidation has already gathered, this performance data can be used to recommend where to place virtualized physical servers in your virtual infrastructure. The second element of Guided Consolidation is the VMware Converter Enterprise application. Once you accept the recommendation from Guided Consolidation, it can also virtualize servers with Converter Enterprise.
- 5nine P2V Planner (for VMware and Hyper-V). Available in a commercial and a free edition, P2V Planner analyzes an environment's physical servers' configuration and utilization. From there, it tells you which virtualization hypervisor offers your company the most return on investment and total cost of ownership. An upcoming release will perform the physical-to-virtual (P2V) conversion for you.
While I recommend automated IT environment assessment tools such as Guided Consolidation, these applications will never understand your company's applications the way you do. You are an integral part of the IT environment assessment process because you know which application does what, how it uses resources and how critical it is to your company.
David Davis is the director of infrastructure at Train Signal Inc., a global leader in video training for IT pros. Davis has a number of certifications, including vExpert, VCP, CISSP and CCIE #9369. Additionally, he has authored hundreds of articles and six different video training courses, including the Train Signal VMware ESX Server video training series. His websites are Happy Router.com and VMwareVideos.com.